If you wish to add a membership to a member through an alternative method to the member portal, a new waiver, or an existing waiver - you can do so by adding a membership through your member's contact profile.

First, click "Add New Membership" under the "Membership" section of their member profile: 

Then, select an existing membership which will auto-fill the remaining fields, or create a new membership plan and click "Continue" once the fields are filled out: 

Then fill out the payment section and select "Save Membership": 

The membership will now show in the member's profile: 

For information on turning a non-attending contact into a member, please read this article.